Thank you for your question.
Spiritual war is to do with the mind. It is to do with changing the way we think to the way God thinks. To subordinate the human will to God’s will. The only source of knowledge of God’s will is the Bible. Christ is the supreme example of how we should live and his commandments are what we should live by.
We are engaged in two kinds of Spiritual war
1. Within ourselves in our attempt to live a Christ-like life.
Romans 7:18 For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not. (Read the rest)
Romans 8:1 There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit.
Galatians 5:17 For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that ye would.
Romans 12:2 And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.
1Corinthians 9:27 But I keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, I myself should be a castaway.
2. In preaching to others to convert them from this world to Christ.
Ephesians 6:12 For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.
13 Wherefore take unto you the whole armour of God, that ye may be able to withstand in the evil day, and having done all, to stand.
14 Stand therefore, having your loins girt about with truth, and having on the breastplate of righteousness;
15 And your feet shod with the preparation of the gospel of peace;
16 Above all, taking the shield of faith, wherewith ye shall be able to quench all the fiery darts of the wicked.
17 And take the helmet of salvation, and the sword of the Spirit, which is the word of God:
In the first century AD they preached to a world steeped in Idolatry and Pagan philosophy.
In our day we preach to a world steeped in the Idolatry of covetousness, an apostate Christianity and ‘oppositions of science falsely so called’ (1Timothy 6:20).
For both kinds of war we need a thoroughgoing belief in and understanding of the Bible – the sword of the spirit.
I hope this helps